Windows 10 instalation stuck at 99% configuring process since 8:00 pm yesterday. what can I do?

I'm installing windows 10 upgrade from windows 8.2 on my daugther's notebook (ASUS i7 2.8GHz 8GB RAM) and it has apparently allmost gone well, but now it's configuring and is stuck in 99% from 8:00 pm yesterday to now. what can I do?